Armour model import

I imported the first and second layer of a netherite armor as armour model. Then I changed the design a bit. But every time i try to import the armour again from the desktop, the layers i have already edited are overwritten with an unedited netherite layer instead of adding a new model. It also doesn't help to add a 2 or so to the name before importing, or to paint a stroke in the image so it's no longer the same. Can anyone help me with this?